This grant application is designed to continue our investigations of the possible role of a T cell immune response to DNA in the pathogenesis of cutaneous lupus lesions. The character of the lupus lesion inflammatory infiltrate will be determined employing immunofluorescent antibody techniques utilizing monoclonal T cell and monocyte antisera. The possible presence of B cells will be determined employeing a rabbit F(ab)(2) anti human F(ab)(2) antisera. Isolated T cells collected from small subepidermal blisters produced over lupus lesions will be incubated with tritiated thymidine labelled ssDNA, UVDNA, and nDNA fractions and the ability of these T cells to bind the DNA fractions determined employing autoradiographic techniques. Peripheral blood mononuclear cells co-cultured with and without lupus lesion T cells and ssDNA, nDNA and UVDNA fractions will be evaluated for their ability to immunologically respond by measuring tritiated thymidine incorporation. These studies are designed to detect the presence of T cells in lupus lesions and to test their functional capability to respond immunologically to DNA. In additiona, animal models employing UVDNA sensitized rabbits exposed to UVB, UVC, and UVA light sources will be created to investigate the possible role of epidermal derived DNA in the pathogenesis of the lupus lesions, the formation of immune complexes as well as their possible role in the genesis of glomerulonephritis. The presence of immune complexes will be detected employing a solid phase conglutinin binding assay and I(125) labelled goat anti rabbit globulin. In addition, the presence of DNA antaigens in the immune complexes will be determined using the solid phase conglutinin binding assay and I(125) labelled anti ssDNA and UVDNA antibodies; sodium dodecyl sulfate polyacrylimade gel electrophoresis of concentrated immune complexes followed by blot transfer to nitrocellulose paper. The nitrocellulose paper will then be stained with anti ssDNA and UVDNA antibodies using the perioxidase anti peroxidase technique. These techniques will also be employed to investigate the presence of ssDNA and UVDNA in the immune complexes of SLE patients.